1.
An Assessment of
Increasing Water Use
Efficiency on Demand
Hardening
February 2, 2016

2.
Goal of this Presentation
!! Explain the phenomenon of demand
hardening (Do long-term increases in water
efficiency negatively impact an area’s ability to
cope with water shortages and further reduce
demand?)
!! Outline the concepts of the 2015 AWE study of
seven case studies around the country
!! Provide recommendations for how to avoid
demand hardening in a water supplier service
area

3.
Detailed 2015 Report

4.
Recommended Compendium

5.
What Does Demand
Hardening Mean?
!! Long term investments in water use efficiency
may make adaptations to extended shortages
more difficult
!! Savings from future conservation programs may
cost more (because low hanging fruit has been
plucked)
!! Future price elasticity may be lower (because
discretionary uses will be more efficient)

6.
What Does Demand Hardening Mean?
!! Long term investments in water use efficiency
may make adaptations to extended shortages
more difficult
!! Savings from future conservation programs may
cost more (because low hanging fruit has been
plucked)
!! Future price elasticity may be lower (because
discretionary uses will be more efficient)
may make adaptations to extended shortages
(because low hanging fruit has been

7.
“Efficient Customers Will Have Less
Room to Save During a Shortage”
!! “Less Room”is vague and simplistic
"! Does it refer to “ability” or “willingness” to conserve?
!! Shouldn’t we also think about savings generated
by pre-shortage WUE programs?
"! Banked and used to improve system reliability?
!! no demand hardening by definition
"! Used to supply new growth?
!! per-capita short term adjustment may be less, but total
adjustment, not necessarily

8.
Why Undertake This Detailed
Study?
!! Demand hardening has been a long-running
concern which remains unresolved
"! Because of little prior research on the topic
!! The meaning of demand hardening is
sometimes misunderstood
!! How water suppliers try to deal with the issue is
sometimes misguided

9.
Operationalizing Key Study Questions
!! Do long-term investments in water use
efficiency (WUE) reduce
"! “ability” to conserve, or
"! “willingness” to conserve during shortages?
!! Does shortage adaptability vary by customer
class?
!! How should one go about mitigating demand
hardening?

10.
Study Approach
!! Shed light on the“ability”and“willingness”
questions through
"! Review of end-use metering studies and macro
indicators
"! Analysis of shortage histories spanning over 40 years
(1970-2014) across 7 suppliers (case studies)
"! Telephone survey of (case study) SF customers, and
review of other published opinion survey research

11.
7 Case Studies Are…
!! Boulder, CO
!! Irvine Ranch WD, CA
!! Monte Vista WD, CA
!! Petaluma, CA
!! San Antonio, TX
!! Santa Fe, NM
!! Santa Rosa, CA

12.
End Use Studies: Indoor GPCD
0
10
20
30
40
50
60
70
REUWS 1999 (HH
size=2.8)
REUWS 2015 (HH
size=2.6)
WaterSense Homes (HH
size=3)
69
58
36
IndoorGPCD

13.
End Use Studies: Indoor Behavior
0
0.5
1
1.5
2
2.5
3
3.5
4
4.5
5
Toilet Flushes Per
Capita Per Day
Clotheswasher Loads
Per Capita Per Day
Average Showers Per
Capita Per Day
5
0.3
0.66
5
0.3
0.69
REUWS1999
REUWS2015

14.
International Comparisons
0
20
40
60
80
100
120
140
160
180
200
Israel Spain Italy Australia California
80
96
115
130
192
GPCD
Urban Water Demand circa 2000

15.
US Water Demand & Economic
Growth
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16.
Turning Now To the Case Studies….
!! What can we learn from their shortage
history?

17.
Production History:
Petaluma, CA
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18.
Production History: Santa
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19.
What Do These Production
Histories Tell Us?
!! Granular information about each shortage
event is necessary to determine its severity and
draw lessons
!! Voluntary restrictions generate less impact
than mandatory restrictions
!! Impact of mandatory restrictions does not
seem to be correlated to pre-shortage GPCD

20.
Do High GPCD Suppliers Save
More?
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21.
Telephone Survey Results
!! Only key results are highlighted here
!! Detailed tabulations for each of the seven
(7) participating case studies are available
in the report

22.
Ability to Save In a Future Drought
Compared to a Previous One?
!! 62% thought they had reduced their demand
by up to 30% during the previous drought
!! 74% reported they would be able to repeat this
performance in a future drought
!! While only perceptions, these results do not
indicate declining willingness

23.
Actions Taken During Past Drought,
New Actions Available in Future
!! Almost 90% reduced irrigation or were already
practicing deficit irrigation
!! Majority already have or will consider:
"! Replacing existing landscape with drought-tolerant
plant material
"! Reusing greywater for irrigation
"! Replacing inefficient toilets and clothes washers
"! Altering behavior (shorter showers)

24.
Appetite for Shortage Risk
!! Water rates have risen considerably over the
last few years
"! More than doubling between 1995-2012 in some
case studies
!! Over two-thirds of respondents expressed
readiness to deal with occasional shortages
than pay high water bills
!! Similar to previous opinion research conducted
in San Diego and San Antonio

25.
Where Does the Evidence Lead?
!! “Ability”to curtail demand during shortages
has not bottomed out
!! Evidence also indicates considerable
“willingness”to adapt, but this requires proper
incentives
!! So, is demand hardening a problem or not?
"! Well, it depends…
"! How is the shortage contingency plan configured?
"! How robust are the enforcement mechanisms?

26.
Estimated Residential
Outdoor Use
Case Study Percent of Total Residential Use
in 2013
Boulder, CO 29%
Irvine Ranch, CA 36%
Monte Vista, CA 48%
Petaluma, CA 39%
San Antonio, TX 33%
Santa Fe, NM 17%
Santa Rosa, CA 28%

27.
Implications for Shortage Planning
!! Santa Fe has something to teach us
"! Only two stages in their drought contingency plan
"! Second stage outright bans all residential irrigation
!! Implication: Falling outdoor use may force
suppliers to target indoor uses sooner in a
future shortage
"! May require a different enforcement strategy

28.
Learning From California in 2015
!! January, 2014: Urban water suppliers asked to
reduce their demand by 20%
!! April 2015: Mandatory statewide restrictions go
into effect with goal of saving 25%
!! By November 2015, urban suppliers had
achieved 26% savings compared to similar time
period in 2013
!! The key was enforcement and conservation

29.
Key Conclusions
!! Demand hardening concerns should not deter
long-term investments in WUE
!! Shortage contingency plans must be evaluated
and updated to reflect changing water use
patterns, within and across customer classes
!! Enforcement mechanisms must be thought
through and built into contingency plans

30.
Report and Fact Sheet
Download at:
www.a4we.org/DHreport.aspx